With the rapid development of wearable devices and the progress of manufacturing technology, the smart device becomes an important research field. It involves multi-disciplines comprehensive technologies including materials science, microelectronics technology, micro electro-mechanical technology, nanotechnology, electronic circuits and systems, sensors technology, and so on. The applications thereof have gradually become the priority research area for lots of multinational corporations. Accordingly, flexible pressure sensors, displayers, accumulators and the like have been introduced already. However, the vibration sensor, which is a sensor for important physical parameters, has rarely been reported as a flexible device.
On the other hand, the vibration sensor, which is one of the key components of measuring and testing technique, is mainly used for receiving mechanical parameters and converting the mechanical parameters to proportional electrical parameters. Since it is an electromechanical conversion device, it is also known as transducer, vibration pickup, and the like. Instead of directly converting an original mechanical parameter to be measured to an electrical parameter, the vibration sensor takes an original mechanical parameter to be measured as an input for the vibration sensor, receives it by means of a mechanical receiving part, generates another mechanical parameter suitable for conversion, and finally converts it into an electrical parameter by means of a mechano-electric conversion part. However, traditional vibration sensors can hardly be applied in wearable devices due to some defects such as inflexibility, large size and high power consumption.